Problem 1.8

Two boats, $A$ and $B$, move away from a buoy anchored at the middle of a river along the mutually perpendicular straight lines: the boat $A$ along the river, and the boat $B$ across the river. Having moved off an equal distance from the buoy the boats returned. Find the ratio of times of motion of boats $\tau_{A} / \tau_{B}$ if the velocity of each boat with respect to water is $\eta=1.2$ times greater than the stream velocity.